1. Field
The present application relates generally to the operation of data networks, and more particularly, to methods and apparatus for providing linear erasure codes.
2. Background
In typical wireless delivery systems, content is delivered to portable devices over a multicast transmission channel. The content is in the form of code packets that are coded to overcome packet losses that may occur as packets are transmitted over the transmission channel. An encoder at a transmitter takes the original data packets and produces code packets that are transmitted to one or more devices. Because of noise or other degrading transmission effects, a subset of the code packets is received at any particular device. The received code packets are decoded to recover the original data packets.
Typically, the packet format for use for erasure recovery codes comprises a packet header and packet payload that contains the actual coded data. Conventional systems utilize a different packet header format for each type of erasure code that is used. Unfortunately, this approach is not flexible and does not scale well. For example, if a new encoding type is utilized, then the receivers cannot process those encoded packets without first being updated with special knowledge about how to process the packets. Furthermore, it may be desirable to combine different coding techniques in order to solve or compensate for certain transmission conditions. However, in conventional systems it is generally not possible to combine different coding schemes.
Therefore, what is needed is a system that operates to provide linear erasure encoding that is flexible, scalable, and allows new or combinations of coding schemes without requiring receiving devices to be updated with special knowledge about the encoding scheme being used.